Certified Registered Nurse Anesthetist (CRNA) Practice Exam

What physiological response is caused by vasoconstriction of the alpha receptors?

1. Increased diastolic BP

2. Status quo blood pressure

3. Increased systemic vascular resistance

4. Decreased cardiac output

The correct answer is: Increased systemic vascular resistance

Vasoconstriction of alpha receptors primarily leads to increased systemic vascular resistance. Alpha-adrenergic receptors, when stimulated, cause smooth muscle contraction in blood vessels, leading to their constriction. This narrowed lumen increases the resistance that blood encounters as it flows through the vascular system. As systemic vascular resistance rises, it directly contributes to an increase in arterial blood pressure, particularly diastolic blood pressure, which is a vital aspect of hemodynamic stability. While the response involves changes in diastolic BP, the key effect attributed to the vasoconstriction of alpha receptors is distinctly on systemic vascular resistance. This is foundational in various clinical scenarios, including managing hypotension and guiding the use of vasopressor agents in anesthetic practice. Consequently, understanding that the stimulation of alpha receptors specifically elevates systemic vascular resistance helps elucidate various cardiovascular dynamics, particularly in critical care and anesthesia settings.